Gain adjustment / Balance control
I am planning to build ACA's (as 2 mono blocks) probably point-to-point. I was wondering if it was possible to adjust the gain of the two amps slightly, or to incorporate a variable resistor somewhere to be able to do that. The reason I am thinking of this is because most of the preamp/buffer builds do not have a balance control (like my 30 year old Hafler clone). Some opt for 2 volume pots – one for each channel. I am busy building a B1 for my future ACA’s, but prefer NOT to have 2 volume pots on the B1. However, I would like to be able to adjust the balance between the L and R channels slightly, because of the positioning of the speakers in the room.
Can this be easily done? Or should it rather be a function of the preamp? Or something else in between? Or should I just rearrange my lounge?
I am planning to build ACA's (as 2 mono blocks) probably point-to-point. I was wondering if it was possible to adjust the gain of the two amps slightly, or to incorporate a variable resistor somewhere to be able to do that. The reason I am thinking of this is because most of the preamp/buffer builds do not have a balance control (like my 30 year old Hafler clone). Some opt for 2 volume pots – one for each channel. I am busy building a B1 for my future ACA’s, but prefer NOT to have 2 volume pots on the B1. However, I would like to be able to adjust the balance between the L and R channels slightly, because of the positioning of the speakers in the room.
Can this be easily done? Or should it rather be a function of the preamp? Or something else in between? Or should I just rearrange my lounge?
Newbie post - just trying to do due diligence...
If I use a single 4.6A 19V laptop brick, is it realistic to put a stereo pair of ACA amp boards and the B1 board from Firstwatt in a 2U Mini Dissipante?
I envisage mounting the amp boards on the heat sinks and the B1 in the middle to give me a volume knob on the front panel.
Will the B1 be OK with the ripple from the smps: (is there anything I ought to do in terms of caps to help this)?
thanks
Beardy
If I use a single 4.6A 19V laptop brick, is it realistic to put a stereo pair of ACA amp boards and the B1 board from Firstwatt in a 2U Mini Dissipante?
I envisage mounting the amp boards on the heat sinks and the B1 in the middle to give me a volume knob on the front panel.
Will the B1 be OK with the ripple from the smps: (is there anything I ought to do in terms of caps to help this)?
thanks
Beardy
I am about to finish juma's preamp for the same purpose since I have four ACA channels on top of an F5 in a multi-amped OB system:
http://www.diyaudio.com/forums/pass-labs/254190-best-options-making-f-5-integrated-amp-2.html#post3922510
I am not in a rush as the most music sources already sound Ok for me and I lack some info from Mikkel (Dantimax) to finish the volume attenuator, but I had a few assembled preamp boards tested and they measured clean up to 180-200kHz. the gain is about 8-9dB. use quality components. for example all caps are OSCON. mind you bf862s are smd components if soldering is an issue. you can see my pcb layout in the same thread. good luck.
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Volume control... I just want to confirm what I think I've understood from elsewhere on this thread.
In my case the ACA boards would be driven from a small USB powered DAC. I need some sort of volume control. Can I just use a variable resistor/voltage divider on the input signal or do I have to use a buffer like the b1?
thanks
In my case the ACA boards would be driven from a small USB powered DAC. I need some sort of volume control. Can I just use a variable resistor/voltage divider on the input signal or do I have to use a buffer like the b1?
thanks
And what 24v SMPS do most folks in here has? I was looking at meanwell RS-100-24, 2 per channel, 120mv ripple. Seems to be the best I can find before getting into the über expensive boutique smps's.
USB dac has typical 200 Ohm output impedance, which is low. You can not just connect volume pot before ACA, as it will mess with feedback network. So you should use buffer like B1, but not becuase of DAC output impedance, but for volume pot reasons.
Hi,
I am having some taughts (doubts) about heatsink.
I have a piece of alu, cca 25 cm long, 12.5 cm width with just over 6 cm thickness ( that would be 10 x5 x 2.3 inches), weight is cca 2 kg.
If this would be ok for two channels (cut in half)?
I have some other solutions for aca but this heatsink is alone for long time now
Thanks!
P.s. Why is photo out of proportions when enlarged?
I am having some taughts (doubts) about heatsink.
I have a piece of alu, cca 25 cm long, 12.5 cm width with just over 6 cm thickness ( that would be 10 x5 x 2.3 inches), weight is cca 2 kg.
If this would be ok for two channels (cut in half)?
I have some other solutions for aca but this heatsink is alone for long time now
Thanks!
P.s. Why is photo out of proportions when enlarged?
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I just now read the ACA article so that's the extent of my experience with this amp. Other than the 30 minute warm up time it takes to sound their best, I haven't noticed any break-in with other Pass diy or First Watt components I've built. There is an output capacitor in the ACA circuit that may break-in but it's debatable if it would make an audible difference.
How does it sound so far?
I've been assembling parts for the ACA and have found most everything. Is there a parts list for the hardware stuff? Power switch, standoffs, power jack, the stuff not listed with the electronic stuff. I don't have much understanding of electronics or experience so I'm not real confidant in sourcing the stuff.
Also, I've found plenty of cheap power supplies. Are they all more or less the same? Is there a recommended one out there?
Thanks,
Doug
Also, I've found plenty of cheap power supplies. Are they all more or less the same? Is there a recommended one out there?
Thanks,
Doug